¥2,200,000 (Direct Cost : ¥2,200,000)

Fiscal Year 1996 : ¥2,200,000 (Direct Cost : ¥2,200,000)

Keywords

Supercritical Drying / Drying / Silica Aerogel / Porous Material

Research Abstract

Drying of silica alcogels using supercritical carbon dioxide was carried out at various conditions to investigate the optimal drying conditions for samples with different sizes. From the experiments it was found that a non-equilibrium interface that appeared in fluid phase in some gels, while the tem perature had a minor influence on the time. An increase in the sample thickness affected all stages of the drying process seriously, resulting in longer drying times. Hydrophobic modification of silanol groups on the gels was also performed in the middle of the supercritical drying process using three methylmethoxysilanes. The effects of the hydrophobic modification were evaluated by measuring water adsorption. The aerogel samples modified with methyltrimethoxysilane in the supercritical fluid phase showed higher hydrophobictiy than those modified in the liquid phase prior to the supercritical drying process.